Composite panel

ABSTRACT

A composite panel comprises an outer skins and an inner core. The inner core includes a frame, an elastomeric material disposed between at least a portion of the frame and the outer skin, and a foamed polymer filler. Also disclosed is a method of manufacturing the same.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 12/257,231 filed in the United States Patent and TrademarkOffice on Oct. 23, 2008, the disclosure of which is incorporated hereinby reference and priority to which is claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to composite panels and, in particular, toa composite panel with improved miscellaneous load bearing capabilities.

2. Description of the Related Art

Composite panels are well known. U.S. Pat. No. 5,633,063 issued on May27, 2007 to Lause et al. and U.S. patent application Ser. No. 11/800,705published on Nov. 8, 2007 to Edwards both disclose composite panels andmethods of manufacturing the same. Conventional composite panelsgenerally comprise an inner foam core disposed between a pair of rigidouter skins. The foam core is secured to the skins by an adhesive orthrough mechanical means. The composite panel may be used to constructbuildings and other structures.

Conventional composite panels rely primarily on their outer skins forstrength. When a load is applied to the panel, outer portions of thepanel are subject to high tensile and compression forces. Inner portionsof the panel are subject to progressively less tensile and compressionforces the closer they are to a neutral axis of the panel. This allowsthe inner core to be formed from lighter, cheaper materials such asfoamed polymer. However, if the outer skins become cracked, or otherwisedamaged, the integrity of the panel may be compromised under stress.There is accordingly a need for a composite panel with improved loadbearing capabilities.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a composite panelwith improved load bearing capabilities. In particular, it is an objectof the present invention to provide a composite panel having an internalframe to improve the load bearing capability of the panel.

In one embodiment the composite panel comprises an outer skin and aninner core. The inner core includes a frame, an elastomeric materialdisposed between at least a portion of the frame and the outer skin, anda foamed polymer filler.

In a preferred embodiment the composite panel comprises an acrylonitrilebutadiene styrene outer skin and an inner core. The inner core includesa steel frame having tubular frame members, an elastomeric materialdisposed between at least a portion of the frame and the outer skin, anda polyurethane filler. The outer skin has a ceramic coating.

A method of manufacturing the composite panel includes the steps of:

-   (a) constructing a frame;-   (b) constructing an outer skin cavity to receive the frame;-   (c) securing an elastomeric spacer to the outer skin cavity;-   (d) securing the frame to the elastomeric spacer; and-   (e) filling the area in the outer skin cavity not occupied by the    frame or elastomeric spacer with a foamed polymer filler.

The composite panel may be used in a variety of applications includingbut not limited to the construction of buildings, scaffolding systems,formwork systems, fences, highway barriers, decks, and docks. Thecomposite panel may also be used to form component parts of lightweightvehicles including sunroofs, automobile doors, truck boxes, trainboxcars, shipping containers, boat hulls, etc. Other applications mayinclude the use of the composite panel as part of an article offurniture such as a counter, bookcase, desk, table, or chair; or as partof an appliance such as a refrigerator or walk in freezer.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be more readily understood from the followingdescription of preferred embodiments thereof given, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective end view showing a section of an improvedcomposite building panel;

FIG. 2 is another perspective end view showing a section of thecomposite building panel of FIG. 1;

FIG. 3 is an elevation front view of an improved composite panel havingan opening shaped in the form of a door;

FIG. 4 is an elevation front view of an improved composite panel havingan opening shaped in the form of a window;

FIG. 5 is an elevation front view of a building comprising the compositepanels of FIGS. 2 and 3;

FIG. 6 is a perspective exploded view showing a frame and an outer skincavity used to manufacture the composite building panel of FIG. 1;

FIG. 7 is a perspective view showing the frame married to the outer skincavity during the manufacture of the composite building panel of FIG. 1;

FIG. 8 is a sectional view showing a metal plate used when the outerskin cavity is filled with foamed polymer during the manufacture of thecomposite building panel of FIG. 1; and

FIG. 9 is a perspective exploded view showing a frame and an outer skincavity used to manufacture the composite building panel of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings and first to FIGS. 1 and 2, these show asection of an improved composite panel 10. The panel 10 has a rigidouter skin 12 which, in this example, is vacuum formed fromacrylonitrile butadiene styrene. The outer skin 12 has a web 13extending along its peripheral edges thereby forming a cavity. A coating16 may be applied to the outer skin 12 to protect against environmentaldamage. Suitable interior and exterior ceramic coatings are availablefrom EnviroCoatings (Canada) Inc. of 5730 Production Way, Langley,British Columbia, Canada V3A 4N4. In this example, the outer skin 12 andcoating 16 provide a brick profile for use as an exterior façade of abuilding 100, which is shown in FIG. 5. In other examples, the outerskin 12 and coating 16 may provide other desired profiles including butnot limited to siding, stone, and stucco.

An internal frame is defined by a plurality of frame members 20 a and 20b disposed within a suitable low cost, light weight foamed polymerfiller 24 such as polyurethane. A planar side 14 of the filler 24, whichis opposite of the outer skin 12, may provide a profile suitable for aninterior wall of the building 100 which is shown in FIG. 5. As shown inFIGS. 1 and 2, there is at least one elastomeric stopper 22 a and 22 bdisposed between each frame member 20 a and 20 b and the outer skin 12.Preferably however there are a plurality of elastomeric spacers disposedbetween the frame members and the outer skin. In the drawings a secondelastomeric 22 c stopper is shown disposed between one of the framemembers 20 a and the outer skin 12.

The frame members 20 a and 20 b each respectively abut the elastomericspacers 22 a, 22 b, and 22 c. The elastomeric spacers 22 a, 22 b, and 22c, in turn, each abut the outer skin 12. This allows loads to betransferred from the outer skin 12 to the frame members 20 a and 20 b.The elastomeric spacers 22 a, 22 b, and 22 c also ensure that minimalforce is exerted on the outer skin 12 as the frame members 20 a and 20 bundergo thermal expansion in response to changes in temperature. Theelastomeric spacers 22 a, 22 b, and 22 c also ensure that no noise isdeflected during thermal expansion. Together the frame members 20 a and20 b, the elastomeric spacers 22 a, 22 b, and 22 c, and foamed polymer24 define an inner core of the panel 10.

The frame members may be metal or steel rods similar to frame member 20a. However, the frame members are preferably tubular similar to framemember 20 b. This allows for modular slip-in installation of electricaland plumbing systems during construction of the building 100. As shownin FIG. 1, electrical wiring 26 and water pipes 28 may be received bythe tubular frame member 20 b. In preferred embodiments, tubular framemembers have a wall thickness of 0.049 to 0.250 inches schedule 40steel. Mild steel, galvanized steel, or stainless steel tubing may beused. The tubes may be rounded or squared depending on loadrequirements.

Embodiments of the composite panel disclosed herein have been shown topossess desirable load bearing capabilities. In one example, using 0.090inch schedule 40 steel tubing, a sample composite panel measuring 48inches by 89 inches by 2.75 inches was subject to flexural and axialloading tests by Tony Nairn, Professional Engineer, of British Columbia,Canada. During the flexural loading test the sample composite panel wasplaced horizontally on supports 83 inches apart, and loaded with steeland concrete weights until the mid span deflection reached 1.875 inchesat which point it was judged that bending failure was imminent. Thetotal load applied was 1,026 lbs. When the weights were removed therewas a residual deflection of 0.5 inches. Calculations indicated that theequivalent wind pressure, applied uniformly over the surface of thecomposite panel, would be approximately 52.7 lbs per square foot. A windspeed of approximately 140 miles per hour is required to exert apressure of 52.7 lbs per square foot. If heavier gauge tubing is used,higher wind protection can be accepted.

During the axial loading test, the sample composite panel was verticallyset in a test frame and evenly loaded along its top 48 inch edge by ahydraulic jack, whose hydraulic oil supply pipe was fitted with apressure gauge for calculating the force applied at the top edge of thesample composite panel. Measurements were taken at mid height todetermine the degree of buckling as the load was increased. The samplecomposite panel did not buckle until the load reached 8,000 lbs. At8,640 lbs, the mid height buckling was measured at 2.25 inches outwardsfrom the straight position. This was judged to be the “effective failureload”.

In another example, another sample composite panel measuring 24 inchesby 48 inches by 4 inches was subject to flexural and axial loading testsby Intertek Testing Services NA Ltd. now of 1500 Brigantine Drive,Coquitlam, British Columbia, Canada V3K 7C1. During this flexuralloading test the composite panel laid horizontally, supported at bothends, and load was applied across mid panel. A 3.5 inch timber wasplaced at mid span and centered. A 0.375 inch by 4 inch steel plate wasplaced across the sample composite panel to produce even loading. A loadwas applied using a 10,000 psi pressure gauge and ram, and measuredusing a 5000 lb calibrated load cell with a measurement uncertainty of1.78%. Deflection measurements were taken during loading. The samplecomposite panel achieved a load of 395 lbs and deflection was recordedat 0.22 inches. No structural failure, visible cracks, or delaminationoccurred during this test.

The same equipment was used to perform the axial loading test. Thesample panel was vertically set in a reaction frame and the 0.375 inchby 4 inch steel plate was placed across a top edge of the compositepanel spanning both width and length. The loading apparatus describedabove was used to apply a load to the composite panel to a maximum of4496 lbs. There was no sign of structural failure or permanentdeformation in the sample composite panel.

The above tests show that embodiments of the composite panel disclosedherein can withstand high wind speeds when used as building walls.Furthermore, the axial strength of the composite panel provides adequatesupport for loads from a roof or even additional building stories.

Referring now to FIGS. 3 and 4, individual composite panels 30 and 40similar to the type shown in FIGS. 1 and 2 are shown. In FIG. 3, acomposite panel 30 is provided with an opening 31 which is in the shapeof a door. The opening 31 is provided with mouldings 32, 34, and 36which are disposed on the outer skin. This allows for a door (not shown)to be directly hinged to the composite panel 30. In FIG. 4, a compositepanel 40 is provided with an opening 41 which is in the shape of awindow. The opening 41 is provided with mouldings 42, 44, 46, and 48which are disposed on the outer skin. This allows for a window shutter(not shown) to be directly hinged to the composite panel 40. As shown inFIG. 5, the composite panels 30 and 40 may be used in the constructionof the building 100. The openings 31 and 41 of each of the panels 30 and40 is provided with either a door 60 or window shutter 70, as required,without the need for further processing.

In this example, the composite panels 30 and 40 are truncated to allowfor a pitched roof 50. This simplified structure is ideal for raindrainage and/or collection in tropical climates found in many parts ofthe developing world. However, in other examples, the building 100 maybe provided with any type of roof, flat or gabled, and even multiplestories. The roof 50 and remaining external walls (not shown) are alsoformed from composite panels similar to the type disclosed herein. Thefloor is preferably a concrete foundation slab but may also be formedfrom composite panels similar to the type disclosed herein. Any suitableinterior divider may be used.

Construction of buildings using the composite panels disclosed herein isfast, inexpensive, and simple to teach. Furthermore, specialized labouris not required for either the construction of the building or themanufacture of the panels. Since the composite panels possess desiredflexural and axial strength as well as other desired physicalproperties, the buildings are ideal for use in all types of climaticconditions because of their thermal, water, wind, and earthquakeresistance. The buildings have long term durability and usability. Thecomposite panels weigh approximately 100 lbs each and have a 200 yearlife cycle.

Referring to FIGS. 6 and 7, the first step in manufacturing a compositepanel, used in the construction of buildings, is producing the vacuummoulds used to form the acrylonitrile butadiene styrene cavity 15 whichdefines the outer skin 12 and web 13 thereof. In this example, therealso is a lip 17 which extends along the web 13. Any desired profile maybe provided on the outer skin 12 including but not limited to brick,siding, stone, and stucco. The profile may alternatively be smooth orembedded with customized artwork or designs. A suitable frame 18 is thenformed by welding solid and/or tubular frame members 20 a and 20 b. Ajig can be used to set up the frame for welding with wire hand held orrobotic production welding. The frame 18 may be coated with anon-corrosive material to protect against oxidation.

A plurality of elastomeric spacers 22 a, 22 b and 22 c are secured to aninner face of the outer skin 12 in a configuration to match the frame18. The outer skin 12 is wiped down with acetone, to provide goodadhesive properties, prior to the frame being placed in the cavity 15.The frame 18 is then glue welded to the elastomeric spacers 22 a, 22 band 22 c. Preferably the elastomeric spacers 22 a, 22 b and 22 cmaintain a spacing of 0.25 to 0.375 inches between the frame 18 and theouter skin 12. This allows for foamed polymer to flow freely between theframe 18 and the outer skin 12. In this example, the web 13 is 3 incheshigh creating a cavity 15 which has sufficient volume to create a R22insulation rating when filled with foamed polymer.

As shown in FIG. 8, once the marriage of the frame 18 to the outer skin12 is complete, the assembly is placed in an adjustable squaringcompression chamber and the remaining area in the cavity 15 is filledwith a suitable foamed polymer. Using a foamed polymer having a 31 bdensity generates pressure of approximately 2.08 psi. A ¾ inch steelplate 80 reinforced with angle steel is rested on the lip 17 of thecavity 15, and is bolted to the frame 18, using keeper screwscompression 82 and 84, before foam rises. The keeper screws 82 and 84also keep the frame 18 from moving in the cavity 15. Holes drilled 86and 88 in the steel plate 80 release surplus foam. In this example, thefoamed polymer used is polyurethane. After the foam is set, thecomposite panel can get a final trim to the desired dimensions. The lip17 is also trimmed after the foam is set. The side of the compositepanel, where foam is exposed, may be coated with an acrylic or epoxy forweatherproofing.

Referring now to FIG. 9, when forming a composite panel with an openingfor a door or window, acrylonitrile butadiene styrene cavity 15.1 isformed with the opening 90. In FIG. 9 like parts have been given likereference numerals as in FIGS. 6 and 7 with the additional numericaldesignation “.1”. Mouldings 92, 94, 96 and 98 are formed directly on thecavity 15.1 to allow a window to be hinged directly to the finishedpanel. The panel is then manufactured as described above.

In the construction of a building, galvanized or stainless steelchannels are secured to the concrete foundation slab which is the floorof the building. The channels receive the composite panels which arethen attached to one another using a water based adhesive. The compositepanels are held in place by expandable pipe clamps until they aresecured to the channels using screws. The composite panels arepreferably secured to the channels using 3/16 inch drill screws with apull apart strength of 3000 lbs. This should be sufficient to withstandhurricane winds while still providing flexibility in earthquakes. Inlarger applications welded steel framing may be used to receive thecomposite panels. Coatings can be applied to the surfaces of the securedcomposite panels to improve the aesthetics of the building. The entireprocess is environmentally friendly and produces very little waste allof which is recyclable.

It will be understood by a person skilled in the art that although inthis example the composite panel disclosed herein is used in theconstruction industry that may be used in other applications intransportation and manufacturing industries.

It will further be understood by a person skilled in the art that manyof the details provided above are by way of example only, and are notintended to limit the scope of the invention which is to be determinedwith reference to following claims.

What is claimed is:
 1. A method of manufacturing a composite panelcomprising the steps of: constructing a frame; constructing an outerskin cavity to receive the frame; securing an elastomeric spacer to theouter skin cavity; securing the frame to the elastomeric spacer; andfilling the area in the outer skin cavity not occupied by the frame orthe elastomeric spacer with a foamed polymer filler, wherein the foamedpolymer filler flows between the outer skin cavity and the frame.
 2. Themethod as claimed in claim 1 further including the step of trimming theouter skin cavity to a desired dimension prior to placing the frame inthe outer skin cavity.
 3. The method as claimed in claim 1 furtherincluding the step of wiping the outer skin cavity with acetone prior toplacing the frame in the outer skin cavity.
 4. The method as claimed inclaim 1 further including the step of coating the outer skin cavity witha ceramic coating.
 5. The method as claimed in claim 1 wherein the stepof constructing the frame includes welding tubular, steel frame members.6. The method as claimed in claim 1 wherein the step of forming theouter skin cavity includes vacuum forming an outer skin fromacrylonitrile butadiene styrene.
 7. The method as claimed in claim 1wherein the step of filling the area in the outer skin cavity notoccupied by the frame or the elastomeric spacer with a foamed polymerfiller includes compression filling said area with polyurethane.
 8. Themethod as claimed in claim 1 wherein the step of filling the area in theouter skin cavity not occupied by the frame or the elastomeric spacerwith a foamed polymer filler includes compression filling said area withpolyurethane having a 3 lb density.